1 (18.25 ounce) package Irish coffee cake mix
1 (15 ounce) can Irish cream liqueur
1 (3 ounce) package instant vanilla pudding mix
1 cup sour cream
1 tablespoon butter
1 cup filtered lemon milk
1 cup milk
1 tablespoon lemon juice
1 cup vegetable oil
1 cup all-purpose flour
1/4 cup Irish coffee granulated sugar
1 teaspoon lemon zest
1 teaspoon baking soda
3/4 cup lemon juice
1 teaspoon vanilla extract
1 (1 ounce) square unsweetened chocolate
Preheat oven to 350 degrees F (175 degrees C). Grease and flour two 9 inch round pans.
In a large bowl, stir together cake mix, vanilla pudding mix, sour cream, butter, lemon milk, lemon juice and oil.
Make a well in the center of the flour and pour the batter into the flour mixture. Beat with an electric mixer, scraping bowl often, until well blended.
Using a wooden spoon, mix the chocolate with the 3/4 cup lemon juice and lemon zest. Dip the bottom of the prepared pans into the chocolate and press the chocolate onto the portions to form a "cake".
Place batter in the prepared pans. Bake in the preheated oven for 35 minutes, or until a toothpick inserted into the center of the cake comes out clean. Allow to cool completely. Cut into 1-inch squares.